[seqfan] Re: Giving a mathematical definition to A280001

[Charles Greathouse]

This is a worthwhile project! But I'm not sure that I understand your
question. Being a planar graph is already a standard graph-theoretic
primitive, or is this used in some special way in chemistry?



Charles Greathouse
Case Western Reserve University

On Wed, Feb 1, 2017 at 12:04 AM, Natan Consigli <
origami.experience at gmail.com> wrote:

> Also, I have to mention that the graphs are three-dimensional for
> stereoisomer distinction
>
> On Wed, Feb 1, 2017 at 5:57 AM, Natan Consigli <
> origami.experience at gmail.com
> > wrote:
>
> > Dear Seqfans,
> >
> > I am trying to define A280001 mathematically with graph theory. To let
> the sequence be less "obscure" I have to define what does chemical
> aromaticity mean.
> >
> > Here is what I did so far.
> >
> > As far as being a hydrocarbon I am looking for a connected multigraph
> (non looped for some authors) where each node has degree less than five
> (octet rule).
> >
> > For the condition of being aromatic I need a connected subset of nodes
> that satisfies Huckel's rule. This means that such subset must have the
> following:
> >
> > 1) an alternating connection 1-edge/2-edge vertices (conjugated pi
> system);
> >
> > 2) the number of 2-edge connections must be odd (4n+2 pi electrons);
> >
> > 3) the subset of nodes must represent a chemically planar portion of the
> molecule.
> >
> > I find stating rule 3 in a mathematical way very hard to do. If anybody
> has ideas I would appreciate your help.
> >
> > Natan Consigli
> >
> >
>
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